Expansion piston for pumps



Mar; 3. 1925.

' G. B. M. SMITH EXPANSION PIsToN Fon PUMPS Filed Mal-6h25. 1924 INVENToR.' Geoye/LM ik ATTORNEY.

BY v

Patented Mar. 3, 1925.

UNITED STATES GEORGE B- M- SMIT'H, 0F TQRBANGE, CALIFORNIA.

EXPANSION rIsroN ron PUMPS.

Application led March 25, 1924. Serial No. 701,749.

To all whom it may concern.'

Be it known that I, GEORGE B. M. SMITH, a citizen of the United States, residing at Torrance, in the county of Los Angeles and State of California, have invented certain new and useful Improvements inv Expansion Pistons for Pumps, of which the following is a specification.

This invention relates to pistons and more particularly to pump pistons. i

The main object of the invention is to provide an expansible pump which may be readily expanded to take up wear so as to properly fit the pump cylinder.

A more particular object is to provide a pump piston of the character stated which will be simple in construction, inexpensive to manufacture and eficient in operation, and which may be readily assembled and adjusted.

Other objects and advantages will be made manifest in the following specification for an embodiment of the invention illustrated in the accompanying' drawings, in which:

Figure 1 is a vertical longitudinal section of my pump piston, and a pump cylinder in which the piston is mounted to reciprocate.

Figure 2 is a cross section of my piston taken on line 2--2 of Figure 1.

Referring to the drawings in which like characters of reference desiggnate similar parts, the pump cylinder 1 has been shown, and a piston rod 2 of standard construction is being used. My piston is mounted on the end portion of said rod in said cylinder 1 and comprises an upper head 3, a lower head 4, an externally threaded extension 5 depending axially from said upper head, a rubber washer 6, jaws 7, a plug 8, and a nut 9 which screws on the lower end of said piston rod.

The upper head 3 and its threaded extension 5 are provided with an axial conical bore 10, through which is extended the conical portion 11 of the piston rod 2, the upper face ofsaid head engaging the annular shoulder 1.2 on said rod at the upper end of said conical portion. The lower head 4 is provided with a cylindrical axial bore 13 through which extends the lower cylindrical end 14 of the piston rod 2, the upper face of said head engaging the lower end of the extension and the annular shoulder 15 on the piston rod 2 between the lower end of the conical portion 11 and the upper end of the lowerl end portion 14. The jaws 7 are provided with straight cylindrical outer faces 16 and with conical inner faces 17 which converge upwardly. The plug 8 Ihas a threaded axial opening 18 in threaded en gagement with the threaded extension 5, and the outer face 19 is conical to engage the inner conical surface 17 of the jaws 7, whereby the plug 8 is wedged between the extension 5 and the jaws 7, which jaws surround the plug and extension. The jaws 7 are provided with annular grooves 2O in their peripheries in which are fitted split' spring rings 21 for holding the jaws 7 assembled" on the plug 8,'and the washer 6 surrounds the jaws 7. The plug 8, jaws 7 and Washer 6 are placed between the heads 3 and 4 which engage the upper and lower ends of said jaws and washer. The nut 9 engages thelower face of the lower head 4 and causes the upper face ofthe head to engage the shoulder 15, jaws 7 and washer 6,l whereby the head V3 is held against the shoulder 12, and the jaws 7 and washer 6 are clamped between the heads 3 and 4. '1`he plug 8 is provided with sockets 22 to receive pins 28 projecting from the upper face of the upper head 3, whereby the 'plug 8 may be screwed on the extension 5 or un-V screwed therefrom, when the lower head 4 is rotated. The head 4 is provided with sockets 24 to receive the ends of a wrench 25 whereby the head 4 upon loosing the nut 9 may be rotated to rotate the plug 8 as hereinbefore described.

Upon screwing the plug 8 upwardly on the extension 5 the plug 8 wedges the jaws 7 outwardly, and said jaws expand the washer 6 outwardly into contact with the interior of the cylinder 1, thus taking up the wear between the cylinder and the piston and causing the said piston to lit the cylinder.

Having thus described my invention what I claim is:

In combination, a piston rod formed with a shoulder, a piston comprising an upper head formed with a threaded extension, said head and extension having an axial bore to receive the piston rod, a wedge shaped plug on said extension in threaded engagement therewith, jaws surrounding said plug and having wedging inner surfaces engaging the wedging outer surface of said plug, a washer surrounding said jaws, said upper head engaging the shoulder on said rod, said 5 plug having sockets in its lower end,-a lower head on said piston rod, pins on said lower head engaging said sockets in said plug, said lower head having sockets for receiving a wrench, and a nut screwed on the lower end of said piston rod against said lower head. 10

In testimony whereof I aHiX my signature.

GEORGE B. M. SMITH. 

